Males, but not females, contribute to sexual isolation between two sympatric species of Gambusia
Males, but not females, contribute to sexual isolation between two sympatric species of Gambusia
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DOI：
10.1007/s10682-009-9343-z
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发表时间：
2010-07-01
影响因子：
1.9
通讯作者：
Aspbury, Andrea S.
中科院分区：
文献类型：
--
作者：
Espinedo, Celeste M.;Gabor, Caitlin R.;Aspbury, Andrea S.
生殖隔离限制了物种间的遗传交换。各种交配前和交配后的障碍，如行为、生理和配子不相容，已被证明在共交体中进化。在某些情况下，隔离可能是不对称的，在这种情况下，物种不同地喜欢同种。我们通过两性间亲和赤鼠和盖氏赤鼠的同种配偶偏好来检验性隔离。为了调查雄性对性隔离的贡献，我们比较了两个物种中同种或异种雌性的交配尝试（性腺推力）次数。我们还研究了在同种或异种雌性存在的情况下雄性精子的启动和消耗。然后，我们测量了两个物种中雌性对同种或异种雄性的偏好。我们发现两种雄虫都倾向于与同种雌虫交配，但在同种雌虫和异种雌虫之间精子的产生和消耗没有差异。两种植物的雌性都不喜欢同种的雄性而不喜欢异种的雄性。本研究结果表明，性隔离可能是由雄性配偶选择介导的，而不是由雌性配偶选择介导的，这表明亲和鸡雌雄之间存在不对称的生殖隔离，但存在对称的种隔离。
Reproductive isolation restricts genetic exchange between species. Various pre- and post-mating barriers, such as behavior, physiology and gametic incompatibility, have been shown to evolve in sympatry. In certain scenarios, isolation can be asymmetrical, where species differentially prefer conspecifics. We examined sexual isolation via conspecific mate preference between Gambusia affinis and G. geiseri in both sexes. To investigate male contribution to sexual isolation, we compared the number of mating attempts (gonopodial thrusts) directed at either a conspecific or a heterospecific female, in both species. We also examined sperm priming and expenditure in males in the presence of conspecific or heterospecific females. We then measured female preference for either a conspecific or heterospecific male, in both species. We found that males of both species preferred to mate with conspecific females, but showed no difference in sperm production or expenditure between conspecific and heterospecific females. Females of both species did not prefer conspecific over heterospecific males. Our results suggest that sexual isolation might be mediated by male mate choice in this system and not female choice, suggesting that there is asymmetrical reproductive isolation between the sexes in G. affinis and G. geiseri, but symmetrical species isolation.